The human heart is divided into four chambers. These include the right atrium, the right ventricle, the left atrium, and the left ventricle. The right atrium and right ventricle are divided from the left atrium and left ventricle by a muscular wall call the septum. The atrial septum is the wall separating the atria and the ventricular septum is the wall separating the ventricles.
Several occlusion defects exists which can affect the septa of both children and adults. Example of such occlusion defects can include patent ductus arteriosus, patent foramen ovale (PFOs), atrial septal defects (ASDs), and ventricular septal defects (VSDs). Although the causes and physical characteristics of these defects can vary, each of these defects is generally a small passage, flap, or hole in the septum which allows blood to shunt between chambers in the heart where there is generally no blood flow in a normal, healthy heart. Shunting of this type can result in a number of health problems.